Relationship between seasonal variation in isoprene emission and plant hormone profiles in the tropical plant Ficus septica.

In Ficus septica, the short-term control of isoprene production and, therefore, isoprene emission has been linked to the hormone balance between auxin (IAA) and jasmonic acid (JA). However, the relationship between long-term changes in isoprene emission and that of plant hormones remains unknown. This study tracked isoprene emissions from F. septica leaves, plant hormone concentrations and signalling gene expression, MEP pathway metabolite concentrations, and related enzyme gene expression for 1 year in the field to better understand the role of plant hormones and their long-term control. Seasonality of isoprenes was mainly driven by temperature- and light-dependent variations in substrate availability through the MEP route, as well as transcriptional and post-transcriptional control of isoprene synthase (IspS). Isoprene emissions are seasonally correlated with plant hormone levels. This was especially evident in the cytokinin profiles, which decreased in summer and increased in winter. Only 4-hydroxy-3-methylbut-2-butenyl-4-diphosphate (HMBDP) exhibited a positive connection with cytokinins among the MEP metabolites examined, suggesting that HMBDP and its biosynthetic enzyme, HMBDP synthase (HDS), play a role in channelling of MEP pathway metabolites to cytokinin production. Thus, it is probable that cytokinins have potential feed-forward regulation of isoprene production. Under long-term natural conditions, the hormonal balance of IAA/JA-Ile was not associated with IspS transcripts or isoprene emissions. This study builds on prior work by revealing differences between short- and long-term hormonal modulation of isoprene emissions in the tropical tree F. septica.

Plant hormone profile and control over isoprene biosynthesis in a tropical tree Ficus septica.

Plant hormone signalling and the circadian clock have been implicated in the transcriptional control of isoprene biosynthesis. To gain more insight into the hormonal control of isoprene biosynthesis, the present study measured plant hormone concentrations in jasmonic acid (JA)-treated leaves of our previous model study, examined their relationship with gene expression of isoprene synthase (IspS) and hormone signalling transcription factors. Of the plant hormones, IAA and JA-Ile and their related transcription factors (MYC2 and SAUR21) were significantly correlated with IspS gene expression. Concentrations of cytokinins, isopentenyladenine (iP), trans-zeatin riboside (tZR) and cis-zeatin riboside (cZR), were similarly significantly correlated with IspS expression. However, there was no significant correlation between their related transcription factor (ARR-B) and IspS expression. The circadian clock-related gene PRR7, but not the transcription factor LHY, was highly correlated with IspS expression. These results suggest that the hormonal balance between JA-Ile and IAA plays a central role in transcriptional regulation of IspS through the transcription factors MYC2 and SAUR21, the early auxin responsive genes. The putative cis-acting elements for SAUR on the IspS promoter (TGTCNN and CATATG), in addition to the G-box for MYC2, support the above proposal. These results provide insightful information on the core components of plant hormone-related regulation of IspS under coordination with the circadian clock genes.

Expression of cell-cycle-regulating genes in the development of atherosclerosis in Japanese quail (Coturnix japonica).

The levels of mRNA expression in regulatory genes that are involved in the pathological changes of aortic atherosclerotic and fibroblastic intimal thickening was investigated in Japanese quail. The quail were divided into a control diet group and an atherogenic diet group. The quail were euthanized at 2, 4, 8, and 12 wk after consuming either a control diet or an atherogenic diet. Thereafter, both histological and immunohistochemical studies and mRNA expression analysis of the cell-cycle-regulating genes in aortic atherosclerotic lesions were performed on selected ascending aortas and their large branches. In the atherogenic diet group, aortic lipid-containing intimal and atheromatous lesions were seen mainly at 8 and 12 wk, respectively. Semiquantitative reverse-transcription PCR was used to analyze the alterations of mRNA expression on the development of atherosclerotic lesions. Messenger RNA expression of the c-fos and c-src genes showed peak levels at 8 wk in the atherogenic diet group. However, no significant alteration of c-jun mRNA expression was noted during the entire experimental period. According to the progression of aortic atherosclerotic lesions, c-myc mRNA expression in the atherogenic diet group increased chronologically, and the highest level was observed at 12 wk. Alterations in mRNA expression of proliferating cell nuclear antigen and the p27 gene were similar to that of c-myc. The levels of c-myc, proliferating cell nuclear antigen, and p27 mRNA expression was significantly correlated with the degree of aortic atherosclerotic lesion development at 12 wk in our experiment.

[The effect of mexiletine on theophylline pharmacokinetics in patients with bronchial asthma].

Reported side effects of mexiletine, a useful drug for managing premature ventricular contractions (PVC) and ventricular tachycardia (VT), are gastrointestinal symptoms including nausea and vomiting. Theophylline, a bronchodilator, also causes similar gastrointestinal symptoms with its frequency proportional to the increases in its serum concentration. The occurrence of gastrointestinal symptoms is known to increase in combination therapy of mexiletine and theophylline. However, the pharmacokinetic interaction between mexiletine and theophylline has not been clarified. We, therefore, investigated the effects of mexiletine on theophylline pharmacokinetics. Three patients with bronchial asthma complicating PVC and/or VT (one male and 2 females, aged 70.0 +/- 13.1 years) were studied. All patients were given prophylactic theophylline anticipatory for asthmatic attacks, which was followed by oral administration of mexiletine, 200-300 mg daily, for PVC and/or VT. The serum theophylline concentrations in 3 cases were increased from 13.8 to 25.3 micrograms/ml, from 14.6 to 27.8 micrograms/ml, and from 10.4 to 15.4 micrograms/ml, respectively, after the administration of mexiletine. However, significant decreases in theophylline clearance were observed after the administration of mexiletine by 46, 47 and 35%, respectively. (p < 0.05) With a decrease in theophylline dosage, the serum theophylline concentrations decreased, and gastrointestinal symptoms resolved. Theophylline is metabolized mainly in the liver through an oxidative reaction of p-450 enzyme, however, its metabolism is affected by many factors, such as medications and complications. The results of this study indicated that mexiletine decreases the theophylline clearance by inhibiting the p-450 oxidative reaction to theophylline.(ABSTRACT TRUNCATED AT 250 WORDS)

[Fundamental and clinical investigation of clindamycin-2-phosphate in otorhinolaryngological field (author's transl)].

Some laboratory examinations were made with clindamycin-2-phosphate (CLDM-2-phos.). The drug was applied clinically to several otorhinolaryngological infections and the good results were obtained as follows. 1) Observing by biophotometer, the growth of Staphbylococcus aureus FDA 209P was inhibited well by the serum (diluted 10-fold) 30 minutes, 1, 2, 4 hours after 300 mg of CLDM-2-PHOS. were injected intramuscularly. 2) Serum concentration was determined by thin-layer method with Sarcina lutea ATCC 9341 as the test organism. The peak of serum level was obtained at 1 hour after a single intramuscular injection of 5 mg/kg or 10 mg/kg dosis of CLDM-2-phosphate. The peak of blood concentration was 5.4 mug/ml, 5.6 mug/ml respectively. 3) CLDM-2-phosphate concentration in tissues was estimated one hour after intramuscular injection of CLDM-2-Phosphate. The concentrations in blood and palatine tonsilla were 5.0 mug/ml and 2.9 mug/ml respectively after the intramuscular injection of 10 mg/kg. The concentrations in blood and mucous membrane of maxillar sinusitis were 4.1 mug/ml and 2.5 mug/ml respectively after the intramuscular injection of 10 mg/kg. 4) CLDM-2-phosphate was administered by intramuscular injection into 30 cases with various infections in otorhinolaryngological field. The clinical results were excellent in 22 cases (73.3%), effective in 3 cases (10.0%) and ineffective in 5 cases (16.7%). The effectiveness was 83.3%. 5) No side effects were observed in 30 cases.